Precautions: Increased risk of serious infections including TB and fungal. Exclude latent or active TB with a skin test or TB blood test (interferon-gamma release assays or IGRA). Caution in debilitated or high risk of infection. Exclude active hepatitis B infection or carriage. Avoid live virus vaccines and BCG. Do not use with other biologics. May exacerbate pre-exisiting demyelinating disease and heart failure.

Monitoring: Monitor clinically for infection. Periodic CBC. After therapy started, additional TB testing may be indicated for individuals likely to have exposure to TB.

Drug Interactions: Concurrent use of high-dose steroids and other immunosuppressants may increase risk of infection.

Patient Instructions: Avoid live virus vaccines; avoid pregnancy; stop injections and call your doctor if an infection or fever develops that lasts more than a few days

Comments: TNF antagonists are among the most effective treatments for RA. Patients start to respond quickly, usually within 4–6 weeks but maximum response may take 4-6 months. In RA, combined therapy with an anti-TNF drug and MTX is more effective than either drug alone. TNF antagonists are being explored in a range of diseases such as sarcoidosis and inflammatory eye disease. Risk of tuberculosis may be lower with etanercept than other TNF antagonists; comparative risk of adverse effects among individual TNF antagonists is not clear and side effects likely a class effect. Patients may form antibodies to anti-TNF drugs that decrease their effect. Concurrent treatment with MTX may reduce the frequency of this.

Clinical Pharmacology: Half-life is 14 days. Biologic agents are not metabolized and thus have few drug interactions.